Construction
Manual J Quick Calculator
Real Manual J takes hours of room-by-room work. This is the rough estimate for sizing and comparison shopping.
Cooling load (BTU/h)
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- Heating load
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- Cooling tons
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- Heating BTU/sf
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FAQ
How accurate is this? +
Within 15-25% of a proper Manual J on a typical house. Good for shopping; not for permits.
Why so much variation? +
Insulation level can shift load 2x. A 2400 sf passive house needs less heat than a 1000 sf leaky bungalow.